Don't I remember doom developing pretty organically from wolfenstein and a few other (what would now be called) first person shooters around that time? The name "hexen" is coming to mind too. I would put that whole era as the start of something new, so different from the strategy games and side-scrollers that preceded it. Those first person games were the first time I thought computer games were actually more fun than the console systems, which didn't really have anything similar.
Warcraft II and Doom are both examples of, while not being the first in their genres, defining their genres and inspiring every studio to stop what they are doing and make something in that genre.
I think the big difference for me, after playing a lot of Wolfenstein 3D, was two things... The system I had it on didn't have the CPU to run wolf3d in something like a full screen size, it was something like a 386SX/20. By the time DOOM came around I had a much more capable desktop. Secondly, wolfenstein 3d was everything on a flat two dimensional plane of grey floor. There was one size of wall or door tile and everything had the same ceiling height and same wall height.
DOOM having stairs and up/down movement, and vertical elements to the level design was really revolutionary at the time.